GT40 heads and rocker question??

That's no problem using the stock rockers on the GT40 heads. They still use the same pedistal mounts for the rockers.

a1yola said:

would you know the performance difference if I used aftermarket 1.6 roller rockers opposed to the stockers?

Click to expand...

old thread i know, but Im looking for the same answer

There was JUST a thread on this like 2 days ago.

Stock rockers are non roller, stamped, and sloppy. The 1.6 RRs are more efficient, produce less friction and heat, and are more accurate because of their higher stiffness being a solid piece rather than stamped. However, 1.6 ratio is equivalent to the stock ratio, so there is no real flow advantage in them. Some sources say the stock rockers can flex and produce less than 1.6 ratio. Of this I’m not sure.

This being said, the most improvement I’ve seen in a dyno test using 1.7 RRs (larger than stock, therefore making more valve lift) over stock is less than 10HP gain.